At this point in an election season, a campaign's every utterance shimmers with significance. At the same time, this time around, the campaigns have embraced social media. And the social networks, like whiskey, promote disinhibition. (Just ask Anthony Weiner.) Services like Twitter, Facebook and, more recently, the photo-sharing site Pinterest require that we let our guard down. They also mercilessly sideline participants who seem too repressed or officious.

Perhaps none of that crossed Ann Romney's mind when, on joining Pinterest last week, she added the gorgeous "Anna Karenina"—a heart-shattering work by Leo Tolstoy from the 1870s that both Dostoevsky and Nabokov believed was flawless—to her two-entry list of "Books Worth Reading." (The other entry is "The Forgotten Garden" by Kate Morton.) Yet in the kind of book-club circles that also use Pinterest, a passion for "Anna Karenina" usually signals a romantic disposition. It sometimes makes you seem like you're open to an extramarital affair.

"She does a lot of it herself," Zac Moffatt, the digital director of the Romney campaign told me, explaining Ann's Pinterest choices. "She'll send us stuff like 'Here's a recipe.' We might post things. But those are her recipes. It's all her choices."

But the way Romney's private literary canon then ricocheted around the Internet is an object lesson in the anarchy that characterizes online communication. It's now virtually impossible for a campaign to follow the imperative to use social media while also staying—as the hopeful phrase used to go—"on message."

Off-off-message is more like it.

Posting stuff on Pinterest—or on Twitter or Instagram—is less like issuing a carefully crafted statement and more like doing a spontaneous Lana Del Rey impression at a White House reception. It feels expressive and modern, but it's going to be judged and interpreted in ways no handler can anticipate or control.

Launched in beta one year ago by Ben Silbermann of West Des Moines, Iowa, Pinterest is a hypertrophic photo-sharing site that maintains intimate ties with Twitter and Facebook. Now with some 11 million active users, Pinterest has been boasting that it acquired 10 million users faster than any social site in Interest history.

Pinterest users create collages of digital artifacts from the Internet or from their private collections. The collages are called boards. Early jokes about Pinterest called it corny and imagined all the posts to include bunnies and sunbeams. But venture capital of the kind Pinterest attracted doesn't follow mere corniness. From the start, Pinterest boards have disproportionately shown images of coveted consumer goods, and they drive lanes and lanes of lucrative traffic to e-commerce sites. This phenomenon (strongly encouraged by Pinterest) is a large part of what won the company an eye-popping valuation of $200 million from Andreessen Horowitz last fall.

People joining Pinterest often get drawn into the excitement of quick and florid self-expression followed by instant feedback. Still, Ann Romney's move was a little stunning. Mitt Romney's devoted wife—Mormon convert, mother of five, would-be first lady of the United States—champions a chronicle of … an open marriage?

The Karenins, husband and wife, continued living in the same house, met every day, but were complete strangers to one another. Aleksey Aleksandrovich made it a rule to see his wife every day, so that the servants might have no grounds for suppositions, but avoided dining at home. Vronsky was never at Aleksey Aleksandrovich's house, but Anna saw him away from home, and her husband was aware of it.

Let's just say the medium made her do it. Pinterest has been described as "crack for women" (although isn't crack crack for women?). Keeping scrapbooks, chocked with mementos and photos and locks of Ringo Starr's hair, has long been condescended to as a pastime of moms and grandmas, who paste and caption to wile away their waning years on breaks from Sudoku.

But making scrapbooks—or "pinboards," as they're called on Pinterest, since they're on public view—is not always so pathetic. Instead, scrapbooks are a form of highly impressionistic, multimedia autobiography that come with a point-of-view that can be tart, critical, nostalgic and highly biased. People who make scrapbooks are known to snip black sheep out of family photos; to select only the scraps that bolster their version of life's dramas; to smuggle in allusions to secret animosities and secret romances. These scrapbooks survive, and are used to tell family stories. That's no small victory for the authors. Just as history belongs to the victors, family history may belong to the scrapbookers.

In short, women on crack of any kind may not be on their most selfless behavior. They may be emotional. They may be grandiose.

And because Pinterest encourages impressionism and allusiveness and nonverbal womanly connectivity, Romney ended up dipping into meanings she couldn't have intended.

Shouldn't, for one, a political wife—who this very week said maybe she should "do all the talking" for her husband's campaign—be naming American novels as her favorites? With wholesome themes like "stay married to that government tool Karenin, even if he makes you feel dead inside"? It's just an idea.

"Anna Karenina" did, however, win Ann Romney some admirers. Among the Facebook comments on Romney's "Anna Karenina" endorsement came this one by Aparna Mukherjee. "There *is* something pleasingly surprising (subversive?) about a would-be first lady choosing a book that centers on a dissatisfied aristocratic wife committing adultery, leaving her high-ranking govt official husband before inevitable tragic end."

Surprising indeed! Of course, we could all be overthinking this. As Mukherjee concluded, "Or maybe she hasn't read it."

Virginia Heffernan is the national correspondent for Yahoo News. Her column, "Machine Politics," explores the intersection of technology and the 2012 election.